Apparatus for and method of assembling a plastic pull tab with a metal tear strip



Dept. 20, 1966 HENCHERT 3,273,234

J. APPARATUS FOR AND METHOD OF ASSEMBLING A PLASTIC PULL TAB WITH AMETAL TEAR STRIP Original Filed Feb. 10, 1961 INVENTOR Jouu HEHCHEIZTilnited States Patent Oifi 3,273,234 Patented Sept. 20, 1966 Free3,273,234 APPARATUS FOR AND METHOD OF ASSEM- BLING A PLASTIC PULL TABWITH A METAL TEAR STRIP John Henchert, Oak Park, Ill., assignor toContinental Can Company, Inc., New York, N.Y., a corporation of New YorkOriginal application Feb. 10, 1961, Ser. No. 88,473, now Patent No.3,151,766, dated Oct. 6, 1 964. Divided and this application June 19,1963, Ser. No. 289,075

4 Claims. (Cl. 29?. 453) This application is a division of my copendingapplication Serial No. 88,473, filed February 10, 1961, now Patpm No.3,151,766.

This invention relates in general to new and useful improvements inmeans for opening containers, such as cans, and more particularlyrelates to a novel apparatus for and method of connecting a pull tab toa tear strip.

' In order to facilitate the opening of containers, such as cans, therehas been recently developed the practice of weakening a portion of thecontainer, for example a can end, along lines which define a removableportion of the container, which removable portion has been defined as atear strip. The tear strip remains an integral part of the container andit is necessary that means be provided to facilitate the tearing of thetear strip from the container. To this end, a pull tab is provided. Inaccordance with this invention, the pull tab is formed of a resilientdeformable plastic having a plug portion which is passed through aflange defined opening in the tear strip. I

The primary ditilculty of passing a plug portion of a plastic pull tabthrough an opening in a tear strip is that the pressure required toforce the plug portion through the tear strip opening is in excess ofthat required to rupture the tear strip along the weakening linesdefining the same. invention to provide a novel apparatus which willpermit the ready engagement of plug portions in openings in tear stripswith it being assured that no rupturing of the tear strip from theremainder of the container will occur and at the same time the plugportion of the pull tab will have a. sufficiently tight fit within thetear strip opening to assure a scaling of the opening after theconnection has been formed.

Another object of this invention is to provide a novel method ofassembling a plastic pull tab with a metal tear strip by the forcing ofa plug portion of the pull tab through an opening in the tear strip, themethod being of a nature wherein it will be rapidly accomplishedutilizing a punch and die assembly and wherein the desired conncctionmay be constantly formed while assuring that no rupture of the tearstrip will occur.

A further object of this invention is to provide a novel punch and dieassembly for facilitating the insertion of plug portions of plastic pulltabs in openings in relatively thin sheet metal tear strips withoutundesirably forming the tear strip in a manner to prevent the forming ofthe desired mechanical interlock between the plug portions and the tearstrips which must be of a sealed nature, and without rupturing the tearstrips from adjacent portions of containers.

With the above, and other objects in view that will hereinafter appear,the nature of the invention Will be more clearly understood by referenceto the following detailed description, the appended claims and theseveral views ilhutrated in the accompanying drawings.

In the drawings:

FIGURE 1 is a perspective view of an upper portion of a can having ametal can end which is provided with a tear strip and pull tab inaccordance with this invention.

Accordingly, it is the primary object of this FIGURE 2 is a perspectiveview similar to FIGURE 1 and shows the tear strip partially removed.

FiGURE 3 is an enlarged fragmentary perspective view showing. furtherthe general detailsof the tear strip and pull tab combination.

FIGURE 4 is anenlarged fragmentary vertical sectional view taken alongthe line 44 of FIGURE 3,

and shows the specific details of the connection between the pull taband the tear strip.

FIGURE 5 is an enlarged fragmentary transverse vertical sectional viewtaken along the line 55 of FIGURE 3 and shows further the details of theconnection between the pull tab and tear strip, including the fact thatthe pull tab overlies the metal can end on opposite sides of the tearstrip to prevent the accidental rupturing of the can end along theoutline of the tear strip by a downward pressure.

FIGURE 6 is a fragmentary exploded view with parts shown in section ofthe apparatus for inserting the plug portion of the pull tab into thetear strip.

Reference is first made to FIGURES 1, 2 and 3, wherein there isillustrated a conventional type of can which is generally referred to bythe numeral 20, and which includes a can body 21 and a can end 22. Thecan end 22 is preferably formed of a light gauge metal, and it isdesirable that the metal be easily rupturable. As a result, normally thecan end 22 will. be formed of aluminum, although the usual metalsemployed in the making of the can ends may be utilized. The can end 22is secured to the can body 21 by a conventional seam 23. The can 20 isillustrated and described only to set forth one environment of theinvention. The present invention is not restricted to cans, but may beused in all types of containers, etc., where it is desired to remove aportion thereof .without utilizing any opening equipment, such as a canopener in the case of a can.

Reference is now made to FIGURE 3 in particular, wherein the can end 22is illustrated as having a circumferential tear strip 24 which isdefined by a pair of score lines 25, 26 with the score line 25 beingdisposed outermost and being disposed adjacent the seam 23 so that whenthe tear strip 24 is removed, substantially the entire can end 22 withinthe seam 23 will be removed. The score lines 25, 26 are disposedgenerally in concentric relation for the most part of their lengths andthe score line 26 generally defines an inner panel 27.

The starting end of the tear strip 24 is provided with a pull tab, whichis generally referred to by the numeral 28.

The pull tab 28, as is best shown in FIGURES 4 and 5, is formed of aresilient deformable plastic.

The starting end of the tear strip 24 is provided with an opening 29therethrough defined by an annular flange 30. The flange 30 firstextends downwardly and inwardly and is then turned inwardly at a greaterangle, as at 31.

The pull tab 28 is provided with a hollow or tubular plug portion 32adjacent one end thereof. The plug portion extends downwardly from themain part of the pull tab and is provided adjacent its lower end with anannular rib 33 having an upwardly flaring lower portion 34 and agenerally square cut upper shoulder 35. The flared lower portion 34facilitates the insertion of the plug portion 32 through the opening 29and the engagement of the lower edge of the flange 30 with the shoulder35 prevents the' accidental Withdrawal of the plug portion 32 throughthe opening 29. The relationship of the plug portion 32 with respect tothe flange is such to assure a sealing of the opening 29 at all timeseven when a product is packaged in the can 20 under pressure. The lowerportion of the annular flange 30 being inwardly directed, when an upwardpull is exerted on the pull tab 28, the lower portion of the flange 30will be cammed inwardly to more firmly grip the plug portion 32 and thusprevent accidental removal of the pull tab 28 from, the tear strip 24.

Referring now to FIGURE 4 in particular, it will be seen that the pulltab 28 has an elongated body portion 36 which is slightly thinner thanthat portion of the pull tab from which the plug portion 32 depends. Thebody portion is provided adjacent the end thereof remote from the plugportion 32 with an upper transverse rib 37 and a lower transverse rib 38to facilitate the grasping of the pull tab 28 and the exerting of a tearstrip tearing and removal force thereon. It is to be noted that the rib38 is of a thickness so as to rest upon the upper surface of the can end22 in the normal rest at position of the pull tab.

- Reference is now made to FIGURE 6 wherein there is illustrated theapparatus of this invention, the apparatus being particularly adaptedfor facilitating the assembling of the pull tab 28 with the tear strip24 and being generally referred to by the numeral 39. When the plugportion 32 of the pull tab 28 is snapped into the tear strip 24, thereis a tendency for the flange 30, particularly the lower portion thereof,to straighten out. This is undesirable in that the flange 30 shouldretain the configuration illustrated in FIGURES 4 and to provide thedesired connection with the plug portion 32 of the pull tab 28. It is tothis end that the apparatus 39 is provided.

The apparatus 39 includes a base 40 and a relatively movable punch 41. Abore 42 is formed in the base 40 and has an enlarged upper portion 43.The bore 42 is aligned withthe punch 41 and has a coil spring 44 in thelower portion thereof. The coil spring 44 has its upper end bearingagainst an enlarged bottom portion 45 of an ejector pin 46. A lowerportion of a die ring 47 is seated in the bore upper portion 43. The diering 47 has a bore 48 into which the ejector pin 46 projects. The upperportion of the die ring 47 is provided with a seat 49 which correspondsgenerally to the exterior surface of the flange 30 and on which theflange 30 is intended to be seated during the securement of a pull tab28 to a tear strip 24. The die ring 47 is undercut, as at 50, below theseat 49 to receive the rib 33 of the plug portion 32, and it may also beused to limit the upward movement of the ejector pin 46.

When it is desired to assemble the pull tab 28 with the tear strip 24,the can end 22 is seated on the die ring 47 and the pull' tab 28 isseated on the can end in the desired position with the plug portion 32thereof aligned with the opening 29 defined by the flange 30. The punch41 is then moved downwardly to exert a pressure on the upper surface ofthe pull tab 28 in alignment with the plug portion 32. The force exertedby the punch 41 forces the plug portion 32 through the opening 29.However, since the flange 30 is seated on the seat 49, deformation ofthe flange 30 is prevented. As the plug portion 32 of the pull tab 28passes through the opening 29 in the tear strip 24, it engages the upperend of the ejector pin 46 and moves the same downwardly against theresistance of the coil spring 44. When the punch 41 again moves upwardlyafter the seating of the plug portion 32 within the opening 29, theresiliently mounted ejector pin 46 forces the plug portion 32 upwardlywith the result that the can end 22 and the pull tab 28 are strippedfrom the die ring 47 as an assembly.

From the foregoing, it will be seen that novel and advantageousprovision has been made for carrying out the desired end. However,attention is again directed to the fact that variations may be made inthe examples of the invention disclosed herein without departing from ithe spirit and scope of the invention, as defined in the appendedclaims.

I claim:

1. An apparatus for assembling a pull tab having a resil icnt plugportion and a tear strip having a flanged opening therethrough, saidapparatus comprising a die ring having an upper surface for supportingthe tear strip and a recessed flange supporting seat, an opening in saiddie ring below said seat and a spring loaded ejector in the die ringopening, said die ring opening having an annular release portion beneathsaid seat to both form a stop for said ejector and provide an expansionarea for a lower part of said pull tab plug portion projecting beneathsaid seat whereby the plug portion will necessarily be allowed to expandafter it passes through and below the seat, and i a punch aligned withsaid die ring and being movable towards and away from said die ring.

'2. A method of assembling a pull tab having a resilient plug portionand a tear strip having a flange opening for receiving the plug portion,said method comprising the steps of supporting the tear strip includingthe sup porting of the flange defining the flanged opening, snapfittingthe lower part of the plug portion through the flanged opening whilecontinuing to support the flange, resiliently engaging the plug portionas it passes through the flange and then utilizing the resilientengagement with 'the plug portion to remove the assembled pull tab andtear strip from the support therefor.

3. An apparatus for assembling a pull tab having a resilient plugportion and a tear strip having a flanged opening therethrough, saidapparatus comprising a base having a bore therein, a counterbore alignedwith said bore and presenting an outwardly facing shoulder, a die ringseated in said counterbore and resting on said shoulder, said die ringhaving an outer surface for supporting the tear strip and a recessedflange supporting seat, an opening through said die ring incommunication with said bore said die ring opening having an annularrelease portion beneath said seat to both form a stop for said ejectorand provide an expansion area for a lower part of said pull tab plugportion projecting beneath said seat whereby the plug portion willnecessarily be allowed to expand after it passes through and below theseat, an ejector slidably mounted in said opening, a resilient memberseated in said bore and resisting inward movement of said ejector, and apunch aligned with said die ring and being movable towards and away fromsaid die ring.

4. An apparatus for assembling a pull tab having a resilient plugportion and a tear strip having a flanged opening therethrough, saidapparatus comprising a die ring having an upper surface for supportingthe tear strip and a recessed flange supporting seat, an opening in saiddie ring below said seat and a resilient ejector unit in the die ringopening, said die ring opening having an annular release portion beneathsaid seat to both form a stop for said ejector and provide an expansionarea for a lower part of said pull tab plug portion projecting beneathsaid seat whereby the plug portion will necessarily be allowed to expandafter it passes through and below the seat, and a punch aligned withsaid die ring and being movable towards and away from said die ring.

References Cited by the Examiner UNITED STATES PATENTS 2,713,713 7/1955Tuhbs 29235 X 2,799,971 7/1957 Brudney 29525 X 2,947,071 8/1960 Marchant29-453 X CHARLIE T. MOON, Primary Examiner.

1. AN APPARATUS FOR ASSEMBLING A PULL TAB HAVING A RESILIENT PLUGPORTION AND A TEAR STRIP HAVING A FLANGED OPENING THERETHROUGH, SAIDAPPARATUS COMPRISING A DIE RING HAVING AN UPPER SURFACE FOR SUPPORTINGTHE TEAR STRIP AND A RECESSED FLANGE SUPPORTING SEAT, AN OPENING IN SAIDDIE RING BELOW SAID SEAT AND A SPRING LOADED EJECTOR IN THE DIE RINGOPENING, SAID DIE RING OPENING HAVING AN ANNULAR RELEASE PORTION BENEATHSAID SEAT TO BOTH FORM A STOP FOR SAID EJECTOR AND PROVIDE AN EXPANSIONAREA FOR A LOWER PART OF SAID PULL TAB PLUG PORTION PROJECTING BENEATHSAID SEAT WHEREBY THE PLUG PORTION WILL NECESSARILY BE ALLOWED TO EXPANDAFTER IT PASSES THROUGH AND BELOW THE SEAT, AND A PUNCH ALIGNED WITHSAID DIE RING AND BEING MOVABLE TOWARDS AND AWAY FROM SAID DIE RING. 2.A METHOD OF ASSEMBLING A PULL TAB HAVING A RESILIENT PLUG PORTION AND ATEAR STRIP HAVING A FLANGE OPENING FOR RECEIVING THE PLUG PORTION, SAIDMETHOD COMPRISING THE STEPS OF SUPPORTING THE TEAR STRIP INCLUDING THESUPPORTING OF THE FLANGE DEFINING THE FLANGED OPENINGS, SNAPFITTING THELOWER PART OF THE PLUG PORTION THROUGH THE FLANGED OPENING WHILECONTINUING TO SUPPORT THE FLANGE, RESILIENTLY ENGAGING THE PLUG PORTIONAS IT PASSES THROUGH THE FLANGE AND THEN UTILIZING THE RESILIENTENGAGEMENT WITH THE PLUG PORTION TO REMOVE THE ASSEMBLED PULL TAB ANDTEAR STRIP FROM THE SUPPORT THEREFOR.